Device for simultaneously controlling a plurality of variable resistors

ABSTRACT

A device for simultaneously controlling a plurality of variable resistors, in which a pair of bearing members each having a bearing surface consisting of a part of a spherical surface are fixed to the top of an opened bottom casing made of an electrically conductive material and having four side walls, in coaxial relation with a center hole formed through the top. A ball member having an operating shaft extending through the center thereof is rotatably supported by the pair of bearing members so that when the operating shaft is rotated, a plurality of variable resistors mounted on the side walls respectively may be simultaneously controlled. The pair of bearing members as well as the ball member are made of an electrically conductive material, and an elastic member is interposed between the pair of bearing members or in one of them so as to bias the ball member toward one of the pair of bearing members.

United States Patent 1 Oka et al.

[ 1 Mar. 11, 1975 [22] Filed: Dec. 19, 1972 [21] App]. No.: 316,586

[30] Foreign Application Priority Data Dec. 24, 1971 Japan 47-56[U]var-Q1422," m 2 w 1 [52] US. Cl 1. 338/128, 200/6 A, 74/471 XY, 308/72,403/144 [51] Int. Cl 1101c 5/00, G05g 9/02 [58] Field of Search 74/471XY, 471; 308/72; 200/6 A; 338/128; 403/131, 144

[56] References Cited UNITED STATES PATENTS 9/1956 Dodd 74/471 XY 3/1967Jonsson 74/471 XY 6/1967 Nowselski et al 308/72 3,483,888 12/1969 Wurzel308/72 X 3,585,319 6/1971 Payerle 74/471 XY FOREIGN PATENTS ORAPPLICATIONS 1,027,470 4/1958 Germany 308/72 Primary Examiner-Allan D.Hermann [57] ABSTRACT A device for simultaneously controlling aplurality of variable resistors, in which a pair of bearing members eachhaving a bearing surface consisting of a part of a spherical surface arefixed to the top of an opened bottom casing made of an electricallyconductive material and having four side walls, in coaxial relation witha center hole formed through the top. A ball member having an operatingshaft extending through the center thereof is rotatably supported by thepair of bearing members so that when the operating shaft is rotated, aplurality of variable resistors mounted on the side walls respectivelymay be simultaneously controlled. The pair of bearing members as well asthe ball member are made of an electrically conductive material, and anelastic member is interposed between the pair of bearing members or inone of them so as to bias the ball member toward one of the pair ofbearing members,

2 Claims, 6 Drawing Figures m gu/m 1197s 3,870,986

SHEET 2 OF 2 FIG. 4

DEVICE FOR SIMULTANEOUSLY CONTROLLING A PLURALITY OF VARIABLE RESISTORSBACKGROUND OF THE INVENTION The present invention relates to a devicefor simultaneously controlling a plurality of variable resistors. Thecontrol device in accordance with the present invention may be used, forexample, in a stereophonic sound reproduction system in which more thantwo volume controls must be adjusted simultaneously.

There has been proposed a device for controlling simultaneously apluality of variable resistors of the type in which a pair of bearingmembers which defines a bearing surface consisting of a part of aspherical surface are fixed to the top of an electrically conductivecasing having four side walls, in coaxial relation with a center holeformed through the top, and a ball member having an operating shaftextending through the center thereof is rotatably supported by the pairof bearing members so that four variable resistors mounted on the sidewalls may be simultaneously controlled by rotating the operating shaft.However the undesirable clearance between the ball member and thebearing members is objectionable in that the control of variableresistors cannot be effected with a higher degree of accuracy.Furthermore, when the bearing members and the ball member are made of anon-conductive material, the noise or hum is induced in the soundreproduction systems or the like.

SUMMARY OF THE INVENTION One of the objects of the present invention istherefore to eliminate the clearance between the ball member and thebearing members in the device for simultaneously controlling a pluralityof variable resistors of the type described above.

Another object of the present invention is to prevent the introductionof noise or hum when the variable resistors are controlled.

In order to attain the above objects of the present invention, resilientmeans is disposed within the bearing members so as to bias the ballmember toward one of the bearing members, and the bearing members aswell as the ball member are made of an electrically conductive material.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front view of a firstembodiment of the present invention;

FIG. 2 is a bottom view thereof;

FIG. 3 is a partially cross sectional view, on enlarged scale, of aportion thereof;

FIG. 4 is a perspective exploded view thereof;

FIG. 5 is a partially cross sectional view of a second embodiment of thepresent invention; and

FIG. 6 is a perspective view illustrating one of the bearing membersthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment, FIGS. l-4

A square casing l which is made of an electrically conductive materialhas an open bottom. Molded bearings 3 and 4 each having a bearingsurface which is a part of a spherical surface are securely fixed withrivets 5 to the top of the casing l coaxially of a hole 2 formed throughthe top as best shown in FIG. 4. A ball member 8 which is made of anelectrically conductive material and has an operating shaft 7 fittedinto a through hole 6 formed through the center of the ball member 8which is rotatably supported by the pair of bearings 3 and 4. Aring-shaped leaf spring 9 which is made of a conductive material and hasa plurality of projections 10 radially inwardly extending from the innerperiphery thereof is interposed between the pair of bearings 3 and 4 insuch a manner that the projections 10 contact thc ball member 8 so as tobias it in one direction. In the instant embodiment, the ball member 8is biased toward the bearing 3 under the force of the leaf spring 9.

.The wall 11 of the lower bearing 4 serves to limit the angle ofrotation of the operating shaft 7.

Variable resistors 12-15 are securely fixed to the four side walls ofthe casing 1, respectively in such a manner that their shafts 24-27extend through the side walls into the casing 1. In this embodiment, inorder to mount the variable resistors 12-15 on the casing 1, projectionsor ears 20-23 struck out of the ends of shielding bottoms 16-19 of thevariable resistors 12-15 are inserted through engaging holes (not shown)formed in the side walls of the casing l and then bent as best shown inFIG. 2. The variable resistors 12-15 may be of the conventional type.Each of a pair of bow-shaped connecting members 28 and 29 which may bemade of an elastic material, has projections 28a and 29a (the projection29a being not shown) which are struck out from the ends of thebow-shaped connecting member and engage with notches 24a27a formed atthe ends of the shafts 24-27 of the variable resistors 12-15. (Thenotches 25a and 27a are not shown in the figures.) Thus the opposingshafts 24 and 26; and 25 and 27 are interconnected through thebow-shaped connecting members 28 and 29, respectively which cross eachother as best shown in FIG. 2. The leading end 32 of the operating shaft7 is fitted into longitudinal elongated slots 30 and 31 formed in theconnecting members 28 and 29.

Next, the mode of operation will be described. Since the ball-member 8is rotatably supported by the upper and lower bearings 3 and 4, theoperating shaft 7 extending from the ball member 8 may be rotated orshifted in any direction. The end 32 of the operating shaft 7 isslidably fitted into the elongated slots 30 and 31 of the connectingmembers 28 and 29 so that when the operating shaft 7 is rotated, itslower end 32 causes the bow-shaped connecting members 28 and 29 torotate about the axes of the shafts 24 and 26; and 25 and 27. As aresult, the rotation of the bow-shaped connecting members 28 and 29 aretransmitted to the shafts 24-27 of the variable resistors 12-15.Therefore, when the operating shaft 7 is rotated, the resistances of thevariable resistors 12-15 may be simultaneously varied.

When it is desired to adjust only a pair of opposed variable resistors12 and 14 or 13 and 15, one may shift the operating shaft 7 in thedirection in which the other pair of variable resistors 13 and 15 or 12and 14 which are not to be adjusted are disposed, that is, in a planewhich contains the axis of the shafts 17 and 19 or 16 and 18 and isperpendicular to the axis of the shafts l6 and 18 or 17 and 19. In thiscase, the end of the operating shaft 7 slides in the elongated slot 31or 30 without causing the connecting member 29 or 28 to rotate, butcauses the connecting member 28 or 29 to rotate. Thus only one pair ofopposed variable resistors 12 and 14 or 13 and 15 may be adjusted.

Since the leaf spring 9 interposed between the upper and lower bearings3 and 4 serves to bias the ball member 8 in one direction as explainedabove, undesired play of the ball member 8 may be taken up. Furthermorethe ball member 8 which is made of an electrically conductive materialis electrically connected to the casing 1 through the eondustive leafspring 9, and the rivets 5 that the noise may be prevented from beinginduced when the operating shaft 7 is actuated. Second Embodiment, FIG.5 and FIG. 6

The second embodiment shown in FIGS. 5 and 6 is substantially similar tothe first embodiment described above except that a plurality ofresilient projections 9a are formed integral with the wall 10 of thelower bearing 4, thus the leaf spring 9 used in the first embodiment iseliminated.

In the second embodiment, the plurality of resilient projections 9a maybe formed simultaneously when the bearing 4 is molded. Therefore thenumber of parts may be reduced and the assembly may be muchfacilitated,- so that the second embodiment is more economical than thefirst embodiment.

What is claimed is:

1. In a device for simultaneously controlling a plurality of variableresistors of the type in which a pair of molded bearing members eachhaving a bearing surface which is a part of a spherical surface aresecurely fixed to the top of an electrically conductive casing havingfour side walls in coaxial relation with a center hole formed in the topof said casing;

a ball member having an operating shaft extending through the centerthereof is rotatably supported by said pair of bearing members; variableresistors are fixed on the side walls of said casing in such a mannerthat their shafts extend through each side wall into said casing; andthe end of said operating shaft is slidably fitted into elongated slotsformed in bow-shaped elastic connecting members each connecting theopposed shafts of said variable resistors,

a member having a plurality of elastic projections interposed betweensaid ball member and said pair of bearing members so as to contact saidball member and to bias it toward one of said pair of bearing members,and

said pair of bearing members and said ball member being of anelectrically conductive material electrically connected to the casing.

2. A device as defined in claim 1 wherein said member is made of anelectrically conductive material and is interposed between said pair ofbearing members so as to bias said ball member toward one of said pairof bearing members.

1. In a device for simultaneously controlling a plurality of variableresistors of the type in which a pair of molded bearing members eachhaving a bearing surface which is a part of a spherical surface aresecurely fixed to the top of an electrically conductive casing havingfour side walls in coaxial relation with a center hole formed in the topof said casing; a ball member having an operating shaft extendingthrough the center thereof is rotatably supported by said pair ofbearing members; variable resistors are fixed on the side walls of saidcasing in such a manner that their shafts extend through each side wallinto said casing; and the end of said operating shaft is slidably fittedinto elongated slots formed in bow-shaped elastic connecting memberseach connecting the opposed shafts of said variable resistors, a memberhaving a plurality of elastic projections interposed between said ballmember and said pair of bearing members so as to contact said ballmember and to bias it toward one of said pair of bearing members, andsaid pair of bearing members and said ball member being of anelectrically conductive material electrically connected to thecasing.
 1. In a device for simultaneously controlling a plurality ofvariable resistors of the type in which a pair of molded bearing memberseach having a bearing surface which is a part of a spherical surface aresecurely fixed to the top of an electrically conductive casing havingfour side walls in coaxial relation with a center hole formed in the topof said casing; a ball member having an operating shaft extendingthrough the center thereof is rotatably supported by said pair ofbearing members; variable resistors are fixed on the side walls of saidcasing in such a manner that their shafts extend through each side wallinto said casing; and the end of said operating shaft is slidably fittedinto elongated slots formed in bow-shaped elastic connecting memberseach connecting the opposed shafts of said variable resistors, a memberhaving a plurality of elastic projections interposed between said ballmember and said pair of bearing members so as to contact said ballmember and to bias it toward one of said pair of bearing members, andsaid pair of bearing members and said ball member being of anelectrically conductive material electrically connected to the casing.